水肥耦合效应对毛白杨苗木生物量的影响

Coupling effects of water and fertilizer on the biomass of Populus tomentosa seedlings.

水和肥是促进毛白杨速生高产的两大重要因素,研究水肥耦合效应对毛白杨苗木的生物量影响具有重要的现实意义.本文以毛白杨杂种无性系87号嫁接苗为试材,采用水、氮、磷三因素五水平二次回归通用旋转组合设计,于2008年3—10月在北京林业大学苗圃进行盆栽试验,研究了不同水肥耦合水平对毛白杨苗木生物量的影响,并建立了毛白杨生物量的水肥耦合回归模型.结果表明:土壤水分是影响毛白杨生物量的主要因素,其次为氮肥和磷肥.随着三者投入量的增加,毛白杨生物量增加;当三者增加到一定程度时,继续投入则使其生物量下降.土壤水分与氮肥交互作用显著,且有较好的正效应;而氮肥与磷肥、土壤水分与磷肥交互作用不明显.经模型寻优,水肥调控的最佳组合为:土壤水分控制在田间持水量的73.37%,氮肥和磷肥的施用量分别为4.14和1.41 g.plant-1;此时的毛白杨苗木生物量达到68.30 g.plant-1.

Water and fertilizer are the two main factors promoting the fast growth and high-yielding of Populus tomentosa,and thus,to study their coupling effects on the biomass of P.tomentosa seedlings has important practical significance.Taking the P.tomentosa clone 87 seedlings as test materials,a pot experiment with rotary combination design of square regression of three factors with five levels was conducted in the nursery of Beijing Forestry University from March to October 2008 to study the coupling effects of water,fertilizer N,and fertilizer P on the biomass of the seedlings,and a related regressive mathematical model was established.The results showed that water was the main factor affecting the biomass of P.tomentosa seedlings,followed by fertilizer N,and fertilizer P.With the increasing input of the three factors,the biomass of the seedlings increased,but when the input was beyond a certain level,the biomass began to decrease.There was a significant positive interactive effect between water and fertilizer N,but a less interactive effect between fertilizer N and fertilizer P and between water and fertilizer P.In our case,the optimal combination of water and fertilizer was 73.37% of field capacity ＋ 4.14 g·plant-1 of N fertilization ＋ 1.41 g·plant-1 of P fertilization,under which,the biomass of P.tomentosa seedlings achieved 68.30 g·plant-1.